I have an array
data = [{:user=>1399, :job=>10270}, {:user=>2614, :job=>10270},
{:user=>3112, :job=>10270}, {:user=>2614, :job=>10271},
{:user=>1455, :job=>10271}]
Where 1399, 2614, 3112, 1455 are user ids and 10270, 10271 are job ids.
I want to show the number of jobs per user regardless of the job id.
Expected result:
1399 => 1
2614 => 2 # because 2614 has 2 two jobs
3112 => 1
1455 => 1
i need this in an array
First group_by the user key and then count the number of elements in each group:
IMPROVED SOLUTION
data = [{:user=>1399, :job=>10270}, {:user=>2614, :job=>10270}, {:user=>3112, :job=>10270}, {:user=>2614, :job=>10271}, {:user=>1455, :job=>10271}]
data.group_by {|e| e[:user]}
.transform_values(&:size)
# => {1399=>1, 2614=>2, 3112=>1, 1455=>1}
ORIGINAL SOLUTION
data = [{:user=>1399, :job=>10270}, {:user=>2614, :job=>10270}, {:user=>3112, :job=>10270}, {:user=>2614, :job=>10271}, {:user=>1455, :job=>10271}]
data.group_by {|e| e[:user]}
.map{|id, a| [id, a.size]}
.to_h
# => {1399=>1, 2614=>2, 3112=>1, 1455=>1}